This invention relates in general to insulation assemblies and in particular to a perforated faced insulation assembly for a forced gas unit and a method of making the perforated faced insulation assembly.
The term xe2x80x9cforced gas unitxe2x80x9d, as used in this application, means a unit or appliance that includes a blower or fan for forcing the movement of gas, including such equipment as air handling units including air ducts and heating, ventilating, and air conditioning (HVAC) units. Some HVAC units are provided with insulation assemblies for acoustic and/or thermal purposes. Conventional insulation assemblies used in HVAC units typically include a facing layer adhered to a porous insulation layer. The facing layer is typically non-porous such that the facing layer acts as a moisture barrier between air circulated within the HVAC unit and the insulation layer. As such, the facing layer is useful in preventing or at least limiting the damage caused by the condensation of water vapor on or within the insulation layer. In addition, the facing layer acts as windshield, which prevents the flow of air directly across the insulation layer. The importance of preventing or at least limiting the flow of air directly across the insulation layer is twofold. First, in the absence of the facing layer, the insulation layer is susceptible to erosion as caused by the flow of air generated by the blower. Second, if the insulation layer were directly exposed to the flow of air generated by the blower, heat is transferable though the insulation layer by convention. By shielding the insulation layer, the facing layer significantly reduces if not eliminates the convection heat transfer component through the insulation layer. As such, the amount of heat transferred through the insulation layer shielded the facing layer is significantly less than if the facing layer were absent. Accordingly, an insulation assembly having a facing layer provides better thermal insulation properties than an insulation layer without a facing layer. An advantage of using an insulation assembly having improved thermal insulation properties is that the potential for water vapor condensing on the exterior of the HVAC unit is reduced.
A problem with these types of insulation assemblies is that in certain applications the facing layer may become separated from the insulation layer. Specifically, the air flow within the HVAC unit may create a relatively low static pressure region on the exterior or exposed surface of the facing layer when compared to the static pressure acting on the interior or non-exposed surface of the facing layer. The resulting pressure differential between the exposed and non-exposed surfaces of the facing layer may cause the corresponding portion of the facing layer to balloon. This ballooning effect may cause the adhesive bond between the facing layer and the insulation layer to fail, which results in the separation of facing layer and the insulation layer.
An objective of this invention is to reduce the static pressure differential between opposite surfaces of a facing layer of an insulation assembly subjected to the forced movement of gas in a forced gas unit.
Another objective of this invention is to reduce the likelihood of a facing layer and an insulation layer of an insulation assembly from becoming separated from each other when subjected to the forced movement of gas in a forced gas unit.
This invention concerns an insulation assembly for a forced gas unit that achieves the above objects and other objects not specifically enumerated. The insulation assembly comprises an insulation layer and a facing layer attached to each other. The facing layer has a pressure-balancing region with perforations formed in the facing layer. The perforations allow sufficient gas flow through the facing layer for adequately balancing the pressures acting on the facing layer within the pressure-balancing region.
According to another embodiment of this invention there is provided a method for making an insulation assembly for a forced gas unit comprising the steps of providing an insulation supply including an insulation layer and a facing layer attached to each other, cutting the insulation supply and forming perforations in the facing layer.